This invention relates to a carton blank and a carton.
Food must generally be packaged in air tight packaging to avoid infestations. Traditional cereal boxes have four flaps: two end flaps which fold in and are overlain by an interior major flap and an outer major flap. Such a box leaves pin hole openings to its interior at its corners. Thus, to be suitable to contain food, these cereal boxes are provided with an interior air tight bag.
A number of carton designs are known which provide an air tight carton avoiding the need for an air tight bag. One such carton design is used in many milk cartons and is described, in one variation, in U.S. Pat. No. 4,211,357 to Lisiecki issued Jul. 8, 1980. The carton bottom has two major flaps and two end panels which are ears joined between the two major flaps. A heat seal adhesive is applied to the ears and one major flap then the ears are folded in and the major flaps folded down while the carton sits on a mandrel. Pressure and heat is then applied to seal the bottom. The carton top comprises two ears joined between two major panels. The two ears are folded in and a heat seal adhesive applied to the inside top margin of one of the major panels. The top margins of the major panels are then pressed together while heated to seal same. This results in a gable top.
While a gable top carton allows the carton to be sealed after filling, there is considerable empty head space in the carton. The gable top also precludes stacking of the cartons.
Another carton design, often used for long shelf life storage of juice or other liquids, comprises a sleeve with, at its top and bottom, two major panels which each terminate in an ear-half at either end. For each pair of major panels, a heat seal surface is provided on the inside face of the margin of the major panels. After applying a heat sealable material, the pair of major panels is pressed together with heat to form a fin seal. This also joins opposed ear-halves; the ears are then folded down and spot glued to the carton.
The fin sealed carton makes better use of the interior volume of the carton, however, re-closing of such a carton after opening presents difficulties. In some such cartons, it is contemplated that the carton is opened by cutting through the fin seal: in such case, re-closing is not possible. In other such cartons, a re-closeable flap (e.g., a plastic fitment) may be added to the top of the carton. However, such a flap provides only a relatively small access area to the inside of the carton. Thus, while such a flap may be adequate for a carton containing a liquid, in many instances it may not be adequate for a carton containing dry goods.
Both gable top and fin seal cartons require application of pressure from opposite sides to seal the carton top, as well as the presence of a heat sealable material. This increases the difficulty of manufacturing such cartons.
U.S. Pat. No. 6,056,680 issued May 2, 2000 to Spronk-Dik describes an airtight carton which requires the adhesion of a separate material strip to the carton blank.
Accordingly, a need remains for a carton which provides one or more of the following features: an air tight seal prior to initial opening, the ability to be re-closed, and a relatively large access area on opening.
The top of a carton, with opposite main panels and opposite side panels, has an inner and outer major flap hinged to opposite main panels. The outer major flap has a fold line extending along its length in parallel to a hinge line joining the outer major flap and a main panel. At each side panel, an ear has an ear portion hinged to the side panel and an ear portion hinged to the outer major flap. With this arrangement, the carton may be re-closed by pressing the ears down against the outer major flap so that the outer major flap folds about fold line into a concave V-shape.
Accordingly, the present invention provides a carton comprising: a first main panel; a second main panel; a pair of opposed side panels hinged between said main panels; an inner major flap extending along said first main panel and hinged thereto; an outer major flap extending along said second main panel and hinged thereto, said outer major flap having a width so as to overlap along its length with said inner major flap, said outer major flap having a fold line extending the length of said outer major flap and paralleling a hinge line joining said outer major flap to said second main panel; a pair of opposed outwardly projecting ears, each ear having a side panel portion extending from a top of one of said side panels and an outer major flap portion extending from an end of said outer major flap and joined to said ear side panel portion.
According to another aspect of the present invention, there is provided a carton blank, comprising: a first main panel; a second main panel; a medial side panel hinged to said first main panel at a hinge line and to said second main panel at a hinge line; a first major flap hinged to said first main panel at a hinge line; a second major flap hinged to said second main panel at a hinge line, said second major flap having a fold line extending the length of said second major flap and paralleling said hinge line between said second major flap and said second main panel; a medial ear panel hinged to said medial side panel at a hinge line, hinged to said first major flap at a hinge line and hinged to said second major flap at a hinge line.
Other aspects of the invention will become apparent after a review of the following description and drawings.